1. Technical Field
The present disclosure generally relates to a method for improving the adhesion of lubricants to surgical needles. More particularly, the present disclosure is directed to a method for siliconizing surgical needles in which the needles are treated with an acid solution before a siliconizing material is applied to the needles. The present disclosure also relates to needles made by this process having reduced tissue penetration force.
2. Background of Related Art
The siliconization of metallic cutting edges of articles such as, for example, razor blades, hypodermic needles, surgical needles, scissors, scalpels, and curettes, is known. For example, a process is known for preparing a siliconized surgical needle in which an amino alkyl siloxane is applied to the surface of the needle by immersion in a solution or by spraying and then cured at elevated temperature in order to produce a silicone coating. A product sold by Dow Coming under the name “MDX4-4159” can be used as the amino alkyl siloxane, with the heat treatment being carried out for half an hour or longer at about 120° C.
U.S. Pat. No. 3,574,673, the contents of which are incorporated by reference herein, discloses the silicone coating of a cutting edge employing a siliconization fluid containing a mixture of copolymerizable silicones made up of an aminoalkyl siloxane, specifically a (polyaminoalkyl) alkoxysilane, and a dimethylpolysiloxane.
In order to reduce the force of penetration, it is also known to immerse surgical needles in a solution of a condensable polymethyl siloxane in a mixture of n-heptane and xylene and then to remove the solvent by thermal after-treatment for one hour at 100° C. The product sold by Dow Corning under the name “Syl-Off DC 23”, which exhibits an average degree of polymerization of about 8000, is suitable as the condensable polymethyl siloxane.
Other examples include U.S. Pat. Nos. 5,258,013 and 5,458,616 which disclose coating surgical needles with a siliconization material containing an aminoalkyl siloxane and a cyclosiloxane employing ultrasonic radiation. The siliconization material can be applied in a solvent carrier, e.g., hexane or heptane.
The previously known processes produce surgical needles in which the force of penetration is clearly reduced compared with untreated needles. It would be advantageous to provide siliconized surgical needles which exhibit an even greater reduction in penetration force upon repeated passages through tissue during a suturing operation.